FIG. 1 shows an undercarriage having two braces 1 and 1′ referred to respectively as a brace strut and as a side brace, and shown in detail in FIGS. 1A and 1B. These braces are hinged to the leg 4 of the undercarriage and to the undercarriage frame 5. Each brace 1, 1′ comprises two levers: a top lever 3, 3′ and a bottom lever 2, 2′. The levers of a brace are hinged to each other and to the other parts of the undercarriage at their ends, via hinge pins represented by dashed lines in FIGS. 1A and 1B.
Such levers are known and are subjected in operation to large mechanical forces, mainly in compression and in traction, extending along the longitudinal axis of the part (the axis passing through both ends of the part). These levers are made of steel, aluminum, or titanium alloy.
It is known to be advantageous to make such levers lighter in weight in order to facilitate the operation of the landing gear. In addition, and in general, reducing the weight of each component of an aircraft is a perpetual preoccupation.
Documents FR 2 543 054 and EP 0 678 681A1 disclose mechanical parts, in particular connecting rods, that are light in weight since they are made of composite material. Document EP 0 678 681A1 describes a one-piece connecting rod obtained from superposed and assembled-together layers of resin-preimpregnated yarn. Document FR 2 543 054 describes a connecting rod made from a central portion obtained from superposed and assembled-together layers of resin-preimpregnated yarn, and peripheral portion made by winding a resin-preimpregnated filament or tape.
Such composite materials are nevertheless liable to delamination: in use the layers of fibers, filaments, or tapes separate from one another, mainly because of the repeated mechanical forces to which the part is subjected.